A348656 Numbers with record values of the denominator of the harmonic mean of their unitary divisors.

1, 2, 4, 8, 16, 26, 32, 50, 58, 64, 98, 106, 122, 128, 178, 194, 202, 218, 226, 242, 250, 256, 346, 362, 386, 394, 458, 466, 482, 512, 698, 706, 722, 746, 778, 794, 802, 818, 842, 866, 898, 914, 922, 1018, 1024, 1402, 1418, 1466, 1514, 1522, 1538, 1546, 1594, 1618

Offset

1,2

Comments

The corresponding record values are 1, 3, 5, 9, 17, 21, 33, 39, 45, 65, 75, ... (see the link for more values).

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Amiram Eldar, Table of n, a(n), A103340(a(n)) for n = 1..10000

Example

The first 8 terms of A103340 are 1, 3, 2, 5, 3, 1, 4 and 9. The record values, 1, 3, 5 and 9, occur at 1, 2, 4 and 8, the first 4 terms of this sequence.

Mathematica

f[p_, e_] := 2/(1 + p^(-e)); d[n_] := Denominator[Times @@ f @@@ FactorInteger[n]]; dm = 0; s = {}; Do[dn = d[n]; If[dn > dm, dm = dn; AppendTo[s, n]], {n, 1, 1000}]; s

Crossrefs

The unitary version of A348414.

Cf. A103339, A103340.

Sequence in context: A202274 A070789 A302588 * A354146 A354255 A319385

Adjacent sequences: A348653 A348654 A348655 * A348657 A348658 A348659

Keyword

nonn

Author

Amiram Eldar, Oct 28 2021

Status

approved